import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;
import java.sql.Connection;
import javax.sql.DataSource;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;


public class DBUtil {
    private static final String URL = "jdbc:mysql://127.0.0.1:3306/messagewall?characterEncoding=utf8&useSSL=false";
    private static final String USERNAME="root";
    private static final String PASSWORD="080502";
    private  volatile static DataSource dataSource=null;
    //懒汉模式
    private static DataSource getDataSource(){
        //对这个对象进行判断
        if(dataSource==null){
            synchronized (DBUtil.class){
                //对创建这个新对象进行判断
                if(dataSource==null) {
                    dataSource=  new MysqlDataSource();
                    ((MysqlDataSource)dataSource).setUrl(URL);
                    ((MysqlDataSource)dataSource).setUser(USERNAME);
                    ((MysqlDataSource)dataSource).setPassword(PASSWORD);
                }
                }
        }
        return dataSource;
    }
    public static Connection getConnection() throws SQLException {
        return getDataSource().getConnection();
    }
    public static void close(Connection connection, PreparedStatement statement, ResultSet resultSet) {
        if(connection!=null){
            try {
                connection.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(statement!=null){
            try {
                statement.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(resultSet!=null){
            try {
                resultSet.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }

}
